Ukraine's government and pro-Russian separatists have failed to agree on a new round of peace talks, but Ukraine's military says it will prolong a 24-hour cease-fire agreement.

Ukraine's former President Leonid Kuchma -- Kyiv's envoy in talks with Russia, separatists, and the Organization for Security and Cooperation in Europe (OSCE) -- said on December 10 a new round of negotiations should not be held in Minsk in the coming days because separatists had violated a previously agreed cease-fire deal.

Kuchma was quoted by Interfax as saying, "In a situation where the second party is unable to ensure the cease-fire regime, I do not consider this meeting expedient."

He also reportedly said the separatists should "show that they really want peace and not war, and that they fully control their armed formations."

Denis Pushilin, the envoy for separatists in Donetsk, told Interfax on December 10 that Kuchma's remarks confirmed Kyiv is not interested in obeying a September 5 Minsk peace accord and cease-fire deal.

That cease-fire deal has been broken on a daily basis, with more than 1,000 people being killed in eastern Ukraine since the accord was agreed upon in the presence of mediators from Russian and the OSCE.

A new round of peace talks, possibly in Minsk, was expected to be arranged by the end of this week following a "day of silence" truce between Ukrainian government forces and Russian-backed separatists on December 9.

Despite the failure to agree on a new round of peace talks in the days ahead, Ukraine's military announced on December 10 that it would prolong the December 9 truce to give both sides a change to move closer to each other.

In related news, Ukraine's government created a Secretariat for Security Cooperation with NATO and the European Union.

The head of Ukraine's Security Service, Valentyn Nalyvaychenko, introduced the new security body's chief, Yevhen Marchuk, on December 10.

Prime Minister Arseniy Yatsenyuk said on December 9 that Ukraine would act to abandon the neutral "non-bloc status" introduced in 2010 under then President Viktor Yanukovych, who was ousted by pro-Western protesters in February.

Marchuk, a former prime minister and defense minister, said that scrapping that neutrality would give "a new impulse" to Ukraine's cooperation with NATO and the EU.

But he said Ukraine would have to tread a "long and difficult path" before it could join NATO.

Russia, which annexed Crimea from Ukraine in March and supports separatists fighting government forces in eastern Ukraine, vehemently opposes Ukraine joining NATO and wants the alliance to pledge never to accept Ukraine as a member.

Meanwhile, Ukrainian authorities were investigating an explosion early on December 10 at a building in the port city of Odesa where an office collecting assistance for Ukraine's military is based.

The building in central Odesa was empty at the time of the explosion, and authorities said nobody was hurt.

Ukrainian officials said they are treating the explosion as a terrorist attack.

More than 4,300 people have been killed in the conflict in eastern Ukraine since April.

In Washington, U.S. Vice President Joe Biden called upon Ukraine's government to reform the economy and fight corruption -- saying Ukraine cannot afford to lose another chance to change the country for the better.

Biden accused Russian President Putin of using "kleptocracy and oligarchy" as "tools of international coercion."

He said that in such a situation, "fighting corruption is not just about good governance. It's about self-defense. It is about integrity. It is about sovereignty."